System of electrical distribution



W. A. DARRAII.

SYSTEM OF ELECTRICAL DISTRIBUTION. APPLICATION FILED JUIIE II, 1015.

1,365,305. Patented J H, 1921 m IQ WITNESSES INVENTOR W/fl/am A. Dar/"ah.

/ ATTORNEY WILLIAM A. DARRAH, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY,

SYLVAN IA.

A CORPORATION OF PENN- S'YSTEM OF ELECTRICAL DISTRIBUTION.

I Specification of Letters Patent.

Patented Jan. 11, 1921.

Application filed June 11, 1915. Serial No. 83,514.

To all whom it may concern:

Be it known that 1, WILLIAM A. DARRAH, a citizen of the United States, and a resident of Wilkinsbur in the county of Allegheny and State of ennsylvania, have invented a new and useful Improvement in Systems of Electrical Distribution, of which the followin is a specification.

y invention relates to electrical distributing systems, and it has special reference to systems by means of which electromotive forces of constant value may be continuously impressed upon translating devices, irrespective of the voltage fluctuations occurring upon the circuits supplying power to the translating devices.

More particularly, my invention relates to a distributing system by means of which a direct-current circuit that is subject to a Wide range of voltage fluctuations, such as-a trolley circuit, may be utilized to furnish an electromotive force of constant value to a lightin circuit comprisin incandescent lamps.

lectric railway clrcuits are subject to wide ranges of voltage variation because of the varying loads that are supplied with power therefrom. .On direct-current commercial trolley circuits normally rated at about 600 volts, it is not an infrequent occurrence to have the electromotive force vary from slightly below 300 volts to a maximum value of about 650 volts. As a result of these Wide voltage fluctuations, incandescent lamps supplied with power from the tolley circuit have not given satisfactory service because Such lamps are very sensitive to voltage fluctuations. Headlights, which comprise incandescent lamps of high candle power, have likewise been unsatisfactory in their operation because of the fluctuations in the light as a result of the varlations 1n the electromotive forces impressed upon the lamps.

An object of my invention is to provide a distributing system by means of which an incandescent lamp or lamps may be supplied with power from a direct'current trolley circuit .without being subjected to voltage fluctuations which will impair the illuminating qualities of the lamp or lamps. At the same time, the lamps ma be efiicientl o erated at their rated voltliges, the semi b lng contlnuously applied, irrespective of the c rcuit condltions obtaining upon the assoclated direct-current trolle circuit.

Fora better understanding of the nature and scope of my invention, reference may be had to the following description and the accompanylng drawing in which the single figure 1s a dlagrammatic view of a distributing system embodying a form of my invention.

For purposes of illustration, I have shown my invention as applied to a circuit adapted to furnlsh power to the incandescent lamp of a headlight of a trolley car or locomotive. A direct-current trolley conductor 1, for which may be substituted a third rail or any other suitable current-conveying device, is connected through a trolley pole 2 to a local circuit 3 which comprises a current interrupter 4, here shown as relatively movable contact devices 5 and an electromagnet 6. Of course, the propulsion currents for the car are likwise supplied from the trolley conductor 1 through the trolleypole 2, but the circuits for the utilization of these propulsion currents are not here shown. An inductive device 7, shown as a stationary transformer, serves to inductively interlink the local circuit 3 and a constant-potential circuit 8 which supplies energy to the incandescent lamp 9 of a car headlight.

The inductive device 7 comprises a magnetizable core member 10, on one leg of which is disposed a primary winding 11 and on another leg of which is disposed a secondary Winding 12, the latter being connected across the constant-potential circuit 8. The circuit interrupter 4, which is inserted between the local circuit 3 and the primary winding 11 of the transformer 7, serves to intermittenttently energize the winding 11. This is effected, in the system shown, by means of the relatively movable contact members 5 which are intermittently actuated by the electromagnet 6. The electromagnet 6 is provided with a winding 19 upon a core member 15, the former of which is connected in the local circuit 3 and to ground 13 through the primary winding 11. \Vhen direct current flows through the exciting winding 19 to ground, the electromagnet (5 actuates a magnetizable armature l-l, thereby substantially instantaneously interruptin;, the current flow through the primary winding 11. The current flow through the winding 11- is intermittently interrupted by the make-andbreak in the circuit effected by the contact members 5. As the exciting current flowing in the winding 11 varies thusly, the pulsating magnetic flux flowing in the core member 10 generates an alternating electromotive force in the secondary winding 12 which, in turn, is impressed upon the incandescent lamp 9.

The ope ation of the circuit interrupter 4 proceeds at a very high rate, thereby creating pulsations of magnetic flux through the core member 10 that differ from one another by small time increments only. Of course, it will be apparent that other circuit-interrupting means may be substituted for the particular device shown, the purpose of such means being to intermittently excite the primary winding 11 from a direct-current circuit and at a sufliciently high rate to generate a suitable electromotive force in the secondary winding 12. When a circuit interrupter is employed which embodies relatively movable contact members 5, it may be desirable to shunt the contactmembers 5 by a condenser element 16 and a high-resistance element 17. substantially as shown in the drawing. In this manner, the sparking occuring at the contact members 5, by reason of the make and break of the circuit, is substantially eliminated.

To produce an alternating electromotive force of constant value and, consequently, a current of constant value in the circuit comprising the lamp 9, it is essential that the same amount of flux cut the secondary winding 12 at each magnetic flux-pulsation, irrespective ot' the voltage variations occuring upon the trolley conductor 1. To obtain this, the portion of the core member embraced by the secondary winding 12 is so designed that it is magnetically saturated, irrespective of the current flow in the primary winding 11, within reasonable limits. In the particular transformer shown, a magnetic shunt 18 is disposed between oppositely extending legs of the core member 10 in order to furnish a shunt path for the leakage magnetic flux. As the direct-current voltage upon the trolley conductor 1 fluctuates within wide ranges, the magnetic flux generated by the primary winding 11 will continuously vary in accordance therewith, and the flow of magnetic flux through the magnetic shunt 18 will likewise continuously vary. However, the magnetic flux cut by the winding 12 at each pulsation of the flux will remain at 9.

substantially constant value, thereby impressing an alternating electromotive force of constant value upon the incandescent lamp 9.

\Vhile I have shown one embodiment of my invention, it will be apparent that many modifications may be made therein. and that many other devices may be substituted for those herein described, without departin from the, spirit and scope of the appended claims.

I claim as my invention:

1. A distributing system comprising a direct-current circuit subject to fluctuating voltages, acircuit interrupter, a transformer having a core member and primary and secondary windings disposed thereupon, said primary winding being connected to said direct-current circuit through said circuit interrupter and said secondary winding embracing a portion of the core member which is magnetically saturated, irrespective of the voltage fluctuations of said direct-current circuit, and a constalit-potential translating device connected across said secondary winding.

2. A distributing system comprising a direct-current circuit subject to fluctuating voltages, a single transformer having a core member. portions of which are of difi'ercut degrees of saturation and primary and secondary windings disposed thereon. the primary winding being connected to the directcurrent circuit. a circuit interrupter to intermittently excite said primary winding from said dircct-ciu-rciu circuit whereby an electromotive force oi constant value may be induced in said secondary winding.

3. A distributing system comprising a direct-current circuit subject to voltage fluctuations, a transformer having a core member and primary and secondary windings disposed thereupon, the primary winding being connected to the direct-current circuit, and a circuit interrupter to intermittently excite said primary winding from the direct-current circuit, said secondary winding embracing a portion of the core member which is continuously magnetically saturated under all operating voltages obtaining upon said direct-current circuit.

at. A distributing system comprising a direct-current circuit which is subject to a wide range of voltage fluctuations, a circuit interrupter, an inductive device having a core member, a primary winding disposed thereupon which is excited from said circuit interrupter and a winding embracing a portion of said core member which is continuously magnetically saturated, irres ective of the voltage fluctuations of said irect-current circuit, and a constant potential lighting circuit connected to said secondary winding.

5. A distributing system comprising a direct-current circuit, a single inductive device having a core member, portions of which are of different degrees of saturation and windings disposed thereon, and a circuit interrupter to intermittently include and exclude one of said windings from said circuit whereby an electromotive force of constant value may be maintained in the other of said windings.

In testimony whereof, I have hereunto 10 subscribed my name this 28th day of May WILLIAM A. DARRAH. 

